The present invention relates generally to a goggle, and more particularly to a sports goggle for use during a sports activity.
Protective goggles are customarily employed for cross-country skiing, bicycle racing and similar types of sports. During sports events, the athlete's body becomes heated and his breath may carry more heat and moisture than a person who is not physically exercising while wearing glasses or goggles. Hence, one problem which attends athletes wearing sport goggles is the formation of fog on the viewing lens or lenses.
Many proposals have been disclosed for avoiding fogging of goggles such as incorporating air flow ventilation passageways in a goggle frame. For example, small adjustable or non-adjustable apertured passageways are formed in the goggle frame to vent the space between the goggle lens and the wearer's face directly to the atmosphere. Apparently, the direction and quantity of air flow against the inner lens surfaces is not sufficient in these goggles to reduce fogging to a level desired for use by cross-country skiers or others who perspire greatly while skiing. For downhill skiing, double lens appear to work well but do not work as well for cross-country skiing.
Anti-fog coatings have been developed. The disadvantage is that the coatings need to be renewed and some tend to interfere with vision as they become contaminated.
Another known method of reducing fog is to deposit thin transparent metallic films on the surfaces of the lenses likely to fog and then pass current through the films to heat the surfaces to keep the surface temperature above the dew point. The disadvantage of this method is the necessity for electrical leads, switch means, and a portable power supply, all to be carried by the wearer. Additionally, this method reduces light transmission and thus may interfere with visibility.
It is suggested in U.S. Pat. No. 3,012,248 to use double--spaced lens with an intervening enclosed air space to impede the transfer of heat from the innermost to the outermost lens surfaces in an attempt to inhibit fogging. The disadvantage is the added weight and cost due to the extra lens elements and the temporary nature of the solution.
In addition to anti-fogging capabilities, sport goggles must be sufficiently lightweight that they are not an undue burben to the wearer and they must be sufficiently strong and tough to withstand abuse. The goggles must also be comfortable to wear and should be fashionable.